What are the birthstones?
This is a list of birthstones, and a bit about the colour and wear of each gemstone.
January – Garnet. Garnets are found in many colours - mainly red, orange, and yellow, but they can also be green, blue, purple, brown, black, pink and colourless. Garnets have a range of hardness on the Mohs scale of about 6.5 to 7.5. So they are great for everyday wear.
February – Amethyst. Amethyst occurs in primary hues from a light pinkish violet to a deep purple. Amethyst was once included with the most valuable gemstones (along with diamond, sapphire, ruby, and emerald), but it has now lost much of its value due to the discovery of extensive deposits in locations such as Brazil. It is now commonly used in silver designs, which bring out its fantastic colour.
March – Aquamarine. Aquamarine (from Lat. aqua marina, "water of the sea") is a blue variety of beryl and is a relation to Emerald. The deep blue version of aquamarine is called maxixe. Aquamarines are relativity hard but can be brittle, so avoiding hard knocks is advised. (Bloodstone is also this month’s birthstone).
April – Diamond. Diamond is the hardest natural material known, with a hardness of 10 (hardest) on this scale. Diamond's hardness has been known since antiquity, and is the source of its name. When it comes to colour in order of rarity, colourless diamond, by far the most common, is followed by yellow and brown, by far the most common colours, then by blue, green, black, translucent white, pink, violet, orange, purple, and the rarest, red. "Black", or Carbonado, diamonds are not truly black, but rather contain numerous dark inclusions that give the gems their dark appearance.
May – Emerald. Emeralds are a variety of beryl that is green in colour and has a hardness of 7.5 - 8 on the 10 point Mohs scale of mineral hardness. Due to most emeralds being highly included, their toughness (resistance to breakage) is classified as generally poor so any large knocks should be avoided.
June – Pearl. Pearls occur in the wild, but they are rare. Cultured or farmed pearls make up the majority of those that are currently sold. Pearls from the sea are valued more highly than freshwater pearls. Imitation or fake pearls are also widely sold in inexpensive jewellery, but the quality of their iridescence is usually very poor - and generally speaking, artificial pearls are easily distinguished from genuine pearls.Pearls have a tendency to absorb moisture so it is best to avoid submerging them in water or spraying perfume while you are wearing them. (Moonstone & Alexandrite are also birthstones for this month).
July – Ruby. Rubies are pink to blood-red gemstones, a variety of the corundum. Rubies are a relative of sapphire and are in the top three hardest stones on the Mohs scale of hardness.
August – Peridot. Peridot is one of the few gemstones that occur in only one colour: basically an olive green. The intensity and tint of the green however depends on how much iron is contained in the crystal structure, so the colour of individual peridot gems can vary from yellow-green through to olive green to brownish green.
September – Sapphire. Sapphires are one of the hardest coloured stones. They come in Blue, Green, Orange, Pink and Multi-coloured (Parti Sapphires). The only colour they don’t come in is red (these are rubies). Sapphires are fantastic for everyday wear. They are found in many different places; Sri Lanka have Ceylon Sapphires which are a fantastic vibrant blue; and Australia has mainly party ones or a dark blue almost black coloured sapphire. The most prized sapphires are found in the Padar region of Kashmir. These are rarely available as the mines have been on hold since around 1979.
October - Opal. Opals are commonly found in Australia and Asia. They are usually made up as a dome which consist of three layers - two of quartz and one tiny piece of opal between them, or two layers of quartz and one of opal. Because the opal has the quartz glued to the opal it is not advised to get these stones wet or give them a hard life; they should only be worn for special occasions and in a good strong protective setting. (Pink Tourmaline is also this month's birth stone and is far better than opals for everyday).
November – Topaz. Pure topaz is colourless and transparent but is usually tinted by impurities; typical topaz is wine, yellow, pale grey or reddish-orange, blue brown. It can also be made white, pale green, blue, pink (rare) and reddish-yellow or opaque to transparent/translucent. Orange topaz is also known as precious topaz, while Imperial topaz is yellow, pink (rare, if natural) or pink-orange. Brazilian Imperial Topaz can often have a bright yellow to deep golden brown hue, sometimes even violet. Naturally occurring Blue Topaz is quite rare. Typically, colourless, grey or pale yellow and blue material is heat treated and irradiated in order to produce a more desired darker blue.Mystic topaz is colourless topaz which has been artificially coated, giving it the desired rainbow effect. (Citrine is also this month’s birth stone).
December – Zircon. Zircon is a remarkable mineral, if only for its almost ubiquitous presence in the crust of Earth. It occurs in igneous rocks (as primary crystallization products), in metamorphic rocks and in sedimentary rocks (as detrital grains). Large zircon crystals are seldom abundant. Zircon occurs in many different colours, including red, pink, brown, yellow, hazel, black, or colourless. The colour of zircons sometimes can be changed by heat treatment. Depending on the amount of heat applied, colourless, blue, and golden-yellow zircons can be made. These stones are precious gems and should not be confused with Cubic Zirconias, which are synthetic. (Turquoise is also this month’s birthstone).